There are essentially two types of socialists in modern Western democratic politics. Social democrats are effectively what the left is in nearly every Western European and North American country. They might find socialism laudable, but have made peace with enacting changes to capitalism to make it more equitable. Social democrats enacted policies typically referred to as the mixed economy or welfare state, such as Social Security and universal health care. While U.S. Democrats don't use these labels, social democrats generally define the center-left of the political spectrum in the West.
Democratic socialists on the other hand are typically seen as more radical left-wingers and advocate the outright replacement of capitalism with socialism. European parties such as Greece's Syriza or Spain's Podemos aim to drastically reduce inequality through radical changes in policy. Democratic socialists would have government inject itself into the financial system and take control of natural resources to help the broader populace before private profit.
Despite his chosen label of democratic socialist, Bernie Sanders is very much a social democrat. He repeatedly will tell you how much he admires Scandinavia. That region is the modern poster child for social democracy and its countries are the most progressive, happiest, and equal in the entire world. Sanders is not proposing radical policies, but simply what many Europeans have realized is common sense. Even in America, many of his proposals enjoy broad support, just not among elected officials.
What are these policies? In general, social democrats like Sanders want to ensure that every person has access to housing, health care, education, meaningful employment, and transportation. Furthermore, Western socialists of all stripes typically support progressive social policies such as gender equality and tolerance of differences.
In particular however, Sanders advocates for three things that should be the backbone of the Democratic Party. These include reducing economic inequality, removing the rigged influence of the rich on our political system, and of course most importantly, preventing climate change. These aren't just issues that the far left supports. These are broadly popular issues on which our political system is massively out of step with what the public wants.
To address these issues, Sanders wants to do make our taxation system more progressive by ensuring the rich pay their fair share, given how much they benefit from the labor of others. He wants to ensure that every person has access to food, shelter, health care, and a good-paying job.
Politically, Sanders wants to ensure we keep our democracy by furthering the principle of one person, one vote. To do this he would get the big money that the Roberts Court introduced through Citizens United out of political campaigns and would support publicly funded races. Under this system, politicians would no longer have to spend 80 percent of their time begging the rich for money and could instead campaign for the popular support of the people themselves.
Climate change is the most important issue of our time, and I fear that when I am old it will have become the only issue that matters. Sanders proposes taxing carbon and would do what it takes to reduce emissions in a country that emits far more per capita than practically any other industrialized country. Climate change and inequality are intertwined, as the latter enables the former by depriving those most at risk of the power they need to avoid disaster.
Sanders' platform hardly looks like radical socialism. Instead, it is what nearly every Democratic voter would support deep down and what most Americans realize is fair. Sanders simply has the audacity to call himself an actual socialist and for that he is maligned by the press and treated like a joke. His candidacy, however, is not a joke—its purpose is to advance these issues which matter to every-day Americans.